Hydrogen cyanide in cassava, which is a cyanogenic plant, was reported to be transformed into the non-toxic thiocyanate (SCN- ) in cows and is partly eliminated via the milk. Milk SCN- is used in the antimicrobial function of the lactoperoxidase system (LPS) in milk while lactoperoxidase activity was reported to be useful as a possible indicator of somatic cell counts (SCC). We investigated the effects on the hygienic quality of raw milk and milk SCC through supplementation of fresh cassava peel (FCP) in the diets of dairy cattle. Twenty-four Holstein-Friesian crossbred, lactating dairy cows were blocked by lactation first and then stratified random balanced based on days in milk, milk yield, and body weight into three groups of 8 cows each. The treatment groups were: 1) cows fed a control diet of 6.49 kgDM/d of 21% crude protein concentrate together with ad libitum corn silage; and 2) and 3) cows were fed the same control diet supplemented with top-dressed 500 and 1000 g/d of FCP, respectively. Dietary treatments had no effect on nutrient intake, weight change, milk yield or composition. The raw milk exhibited increased SCNconcentration and decreased SCC. FCP supplementation greatly increased the efficiency of the antibacterial activity of the LPS. The results demonstrated that increasing milk SCN- maintained the hygienic quality of the raw milk by supplementing the diets of dairy cattle with FCP. Since there was also a commensurate reduction in the SCC, it may be possible to use FCP supplementation as an alternative measure to prevent mastitis in lactating dairy cows.
